Interest in fabricating monolithic RF amplifiers in silicon has been prompted by interest in miniaturization of circuits for use in cellular telephones, wireless modems and other types of equipment, especially in high frequency bands such as the 1-GHz band. However, a major limitation in making use of large spiral inductors in monolithic circuits is the low frequency and low-Q self-resonance caused by distributed capacitance to the conductive silicon substrate. One way to avoid this limitation is by adding a process step to etch out the substrate underneath the inductor, thereby suspending the inductor over a pit in the substrate. This approach is described in U.S. Pat. No. 5,539,241 and J. Y -C. Chang and Asad Abidi, "Large Suspended Inductors on Silicon and Their Use in a 2-.mu.m CMOS RF Amplifier," IEEE Electron Device Letters, Vol. 14, No. 5, May 1993, page 246-248, both of which are incorporated in their entireties by reference herein. There is a need for achieving the same isolation in a standard semiconductor manufacturing process flow.